Figure

Average concentrations and trends of surface chlorophyll-a in transitional, coastal and marine waters surrounding Europe

Figure Created 04 Aug 2022 Published 04 Aug 2022 Last modified 24 Jan 2024

2 min read

Topics: Water and marine environment

Summer surface chlorophyll-a concentration averages (left) and trends (right), in locations recently updated (last update>2015) with at least 5 years of observations, in the period between 1980 and 2019. Colour keys of symbols and values are included in the legend.

https://www.eea.europa.eu/data-and-maps/figures/average-concentrations-left-and-trends/fig01-129839-mar006-v3.eps/image_large

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European data

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Metadata

Units:: µg/l
Rights:: - Copyrights of the datasets: please take a look at https://www.ices.dk/data/guidelines-and-policy/Pages/ICES-data-policy.aspx and https://www.emodnet-chemistry.eu/data/acknowledgement
- Copyrights of the figure: EEA standard re-use policy: unless otherwise indicated, re-use of content on the EEA website for commercial or non-commercial purposes is permitted free of charge, provided that the source is acknowledged (https://www.eea.europa.eu/legal/copyright). Copyright holder: European Environment Agency (EEA).
Owners:: European Environment Agency (EEA)
Processors:: AZTI
Figure type:: Map

Additional information

• Average chlorophyll-a concentrations were calculated using data from observations in summer (May to September) from the upper 10m of the water column, in locations with annual data for the last 5-year period (2015-2019), transformed to the logarithmic scale.
• Data were aggregated into squares of 0.01 degree × 0.01 degree for coastal stations (within 20km of the coastline) and 0.05 degree × 0.05 degree for open water stations.
• Temporal trends were estimated in locations with data for at least 5 years in the period 1980-2019 and updated in the last 5-year period (2015-2019), using the non-parametric Mann-Kendall test. A p-value of <0.05 was considered to indicate a statistically significant trend.
• Results reflect data availability, which may vary significantly across regions and over time.

Temporal coverage
1980-2019 (the temporal range specified is the maximum range of dates for raw observations but this range varies upon the availability of observations at each location).